RFR: JDK-8165158: Fix zero builds for non-listed architectures

[Tim Bell]

Erik Joelsson wrote:

> Sponsoring the suggested patch.
>
> Matthias, could you verify that I got it right and that it works for
> you? I don't have a setup where I can test such a platform.
>
> Webrev: http://cr.openjdk.java.net/~erikj/8165158/webrev.01/
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8165158

Looks good to me.  Consider this reviewed after we get confirmation from 
Matthias that the suggested fix is working.

/Tim

>
> /Erik
>
> On 2016-08-31 16:36, Erik Joelsson wrote:
>> Hello,
>>
>> I think the second one is better. Is there a bug filed for this?
>>
>> /Erik
>>
>>
>> On 2016-08-30 14:33, Matthias Klose wrote:
>>> The zero build for architectures not explicitly listed fails
>>> currently in
>>> hotspot, because of an unset macro, and the compiler complains about
>>> a single -D
>>> option passed.
>>>
>>> Here are two proposals how to fix these:
>>>
>>>   - Not passing the -D<cpu_define> if it is not set. Afaik the define
>>>     is only used for hotspot builds, not for zero builds.
>>>
>>>   - Provide a fall back for "unknown" zero architectures.
>>>
>>> Matthias
>>
>